Many types of protective headgear or safety helmets are worn by individuals to protect against head injuries. For example, safety helmets providing protection from top impacts, lateral impacts and/or penetrating impacts typically include a rigid outer shell, a shock absorbing layer within the outer shell and a suspension system. An example of such a safety helmet is the SUPER V safety helmet available from Mine Safety Appliances Company of Pittsburgh, Pennsylvania. In such safety helmets, the outer shell, the shock absorbing layer, along with the suspension act to absorb the shock of any impact to the safety helmet.
Safety helmets providing protection from top impacts, lateral impacts and penetrating impacts are subjected to stringent testing requirements. Those safety helmets are tested under Impact Standard ANSI Z89.1-1997 in the United States and under CSA Z94.1-1992 in Canada. Under CSA Z94.1-1992, for example, safety helmets are subjected to a rigorous penetration test in which a heavily weighted, pointed projectile is accelerated to impact the helmet. To satisfy such penetration tests, manufacturers of safety helmets fabricate the outer shell of the safety helmet from a relatively thick layer of a high impact strength material. The thicker the layer, the heavier the helmet, which makes the helmet uncomfortable for the user to wear. This discomfort can result in fatigue and/or a reluctance to use the safety helmet, either of which can result in safety lapses. Furthermore, use of a relatively thick layer of a very high impact strength material results in substantial manufacturing expense.
It is very desirable, therefore, to develop a safety helmet that provides top impact protection, side impact protection and penetration protection that is lightweight and comfortable to wear, as well low cost and simple to manufacture.